Humidity-sensitive ultraviolet curing coating as well as preparation method and application thereof

Abstract

The invention discloses a humidity-sensitive ultraviolet curing coating. The humidity-sensitive ultraviolet curing coating is prepared from the following raw materials in parts by weight: 30-50 parts of light-cured resin; 5 to 15 parts of water-absorbent resin; 10 to 30 parts of an acrylate active monomer; 1-5 parts of a pH indicator; 0.3-1 part of a leveling agent; 10 to 20 parts of water sensitive salt; 2-7 parts of a photoinitiator; the preparation method of the light-cured resin comprises the following steps: adding polyester polyol into a three-neck bottle, carrying out reduced pressure distillation at 100-140 DEG C for 2-4 hours, cooling to be less than or equal to 40 DEG C, adding trace concentrated phosphoric acid, and uniformly mixing for later use; the preparation method comprises the following steps: adding m-xylylene isocyanate and dibutyltin dilaurate into a three-neck flask provided with a stirrer, a constant-pressure dropping funnel and a thermometer, dropwise adding polyester polyol containing strong phosphoric acid at room temperature, mechanically stirring, heating to 50-80 DEG C, and reacting for 2-6 hours; after photocuring, the surface of the coating is kept dry and comfortable, and after encountering certain humidity, the coating absorbs water and changes color to achieve an indicating effect.

Description

Technical Field

[0001] The invention belongs to the technical field of coatings and relates to an ultraviolet light-curing coating, in particular to a moisture-sensitive ultraviolet light-curing coating and a preparation method and application thereof. Background Art

[0002] Water-discoloring paint is a unique technology product designed to provide an intuitive and efficient testing method. When the product is exposed to a certain humidity, the paint will show a red reaction. This color change is a clear signal for detecting whether there is liquid intrusion. Its main purpose is to protect the rights and interests of merchants and consumers. When the product encounters moisture during transportation or use, by observing the color change of the paint, the source of the problem can be quickly determined to avoid unclear responsibilities; this is especially important for electronic devices such as circuits, batteries and mobile phones, because liquid ingress may cause circuit damage, seriously affecting its performance and even life. In addition, through this intuitive identification, consumers and maintenance personnel can quickly identify problems, saving time and energy, and ensuring product quality and safety. In short, it plays an important role in protecting products from moisture, maintaining fair trade in the market, and improving user experience.

[0003] However, at present, this kind of application basically appears in the form of labels, which need to be manually pasted; for example, the Chinese invention patent with application number 202111102979.X discloses a color-changing paper containing color-changing ink or coating, a preparation method and a wristband, which belongs to the field of special paper technology, using water-resistant fiber paper or non-woven fabric as a substrate, and setting a layer of water-soluble polymer layer on the substrate, and then setting a water-discoloring ink or coating layer on the above-mentioned water-soluble polymer layer, and finally setting a layer of water-soluble polymer layer on the color-changing ink or coating layer. This application uses a water-soluble polymer to be set on the surface of the water-resistant fiber paper or non-woven fabric with water-discoloring ink. After a certain period of immersion or vibration, the water-soluble polymer dissolves or swells, resulting in obvious color of the water-discoloring ink. Due to the difference in solubility of water-soluble polymers of different types or different molecular weights, the time required for dissolution and other conditions are different. By selecting different types of water-soluble polymers and their different molecular weights, the time required for immersion color change can be controlled. As the cost requirements for electronic products increase, manufacturers begin to consider the construction costs of such products, so new products emerge as alternatives. Summary of the invention

[0004] In order to solve the above technical problems, the object of the present invention is to provide a moisture-sensitive UV-curing coating.

[0005] In order to achieve the above object, the present invention provides a moisture-sensitive UV-curable coating, the raw materials of which include the following components in parts by weight:

[0006] 30-50 parts of light-curing resin;

[0007] 5-15 parts of water-absorbing resin;

[0008] 10-30 parts of acrylate reactive monomer;

[0009] 1 to 5 parts of pH indicator;

[0010] 0.3-1 part of leveling agent;

[0011] 10-20 parts of water-sensitive salt;

[0012] 2 to 7 parts of photoinitiator;

[0013] The preparation of the photocurable resin comprises the following steps: adding polyester polyol into a three-necked flask, performing reduced pressure distillation at 100-140° C. for 2-4 hours, cooling to ≤40° C., adding a trace amount of concentrated phosphoric acid, and mixing for use; adding m-phenylenedimethyl isocyanate and dibutyltin dilaurate into a three-necked flask equipped with a stirrer, a constant pressure dropping funnel, and a thermometer, dripping the polyester polyol containing concentrated phosphoric acid at room temperature, mechanically stirring and heating to 50-80° C. for reaction for 2-6 hours, determining the -NCO content by a di-n-butylamine method, adding an excess amount of HEA and a mixed solution of an inhibitor when the reaction reaches a metering point, and continuing the reaction for 1-3 hours; when the -NCO content is ≤0.5%, cooling, discharging, and storing in the dark.

[0014] Optimally, the water-absorbing resin is prepared according to the following steps:

[0015] Place acrylic acid and bentonite in a beaker, add water to mix; drop sodium hydroxide solution to neutralize acrylic acid, add N-N'methylenebisacrylamide and ammonium persulfate, stir evenly, and stir at room temperature to polymerize for 1 to 3 hours;

[0016] The product from the previous step was allowed to react in a water bath at 60-80°C for 1-2 hours until the system became viscous and gel-like. The gel product was taken out and placed in a watch glass to dry to constant weight. After being cut into pieces and ground into powder, it was sealed and stored for later use.

[0017] Furthermore, the acrylate reactive monomer is a mixture of one or more selected from lauryl acrylate, isobornyl acrylate, N,N-dimethylacrylamide, 4-hydroxybutyl acrylate, triethylene glycol dimethacrylate, 1,6-hexanediol diacrylate and 2-phenoxyethyl acrylate.

[0018] Furthermore, the pH indicator is at least one selected from phenolphthalein and o-cresolphthalein or a mixture of two thereof.

[0019] Furthermore, the leveling agent is a mixture of one or more selected from the group consisting of an organic silicon leveling agent, an acrylate leveling agent and a modified acrylate leveling agent.

[0020] Furthermore, the water-sensitive salt is a mixture of one or more selected from the group consisting of sodium carbonate, potassium carbonate, sodium bicarbonate, ferrous sulfate, sodium silicate, sodium metaaluminate and sodium phosphate.

[0021] Furthermore, the photoinitiator is a mixture of one or more selected from 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxy-cyclohexyl-phenyl ketone, ethyl 2,4,6-trimethylbenzoylphenylphosphonate and methyl benzoylformate.

[0022] Another object of the present invention is to provide a method for preparing the above-mentioned moisture-sensitive UV-curable coating, comprising the following steps:

[0023] The light-curable resin, water-absorbing resin and acrylic acid ester active monomer in the formula amount are mixed and stirred for 0.5h to 2h; then the pH indicator and leveling agent in the formula amount are added and stirred for 0.5h to 2h;

[0024] Then add the formulated amount of photoinitiator and water-sensitive salt, evacuate the chamber, maintain the pressure and stir for 2h to 4h; defoam under vacuum and discharge the material.

[0025] Another object of the present invention is to provide an application of the above-mentioned moisture-sensitive UV-curable coating, wherein the moisture-sensitive UV-curable coating changes color when it comes into contact with moisture.

[0026] Optimally, the moisture-sensitive UV-curable coating is applied to the electronic product packaging and reacts with light for 5 to 30 seconds to form a moisture-sensitive mark.

[0027] The moisture-sensitive ultraviolet light-curing coating of the present invention is used by using a specific light-curing resin in combination with a water-absorbing resin, a photoinitiator, a pH indicator, a leveling agent, a water-sensitive salt, etc. After light curing, the surface of the coating remains dry and at the same time, when encountering a certain humidity, it absorbs water and changes color to achieve an indicating effect. DETAILED DESCRIPTION

[0028] The moisture-sensitive ultraviolet light-curing coating of the present invention comprises the following components in parts by weight: 30-50 parts of light-curing resin; 5-15 parts of water-absorbing resin; 10-30 parts of acrylate active monomer; 1-5 parts of pH indicator; 0.3-1 part of leveling agent; 10-20 parts of water-sensitive salt; 2-7 parts of photoinitiator; the preparation of the light-curing resin comprises the following steps: adding polyester polyol into a three-necked flask, performing reduced pressure distillation at 100-140°C for 2-4h, cooling to ≤40°C, adding Add a trace amount of concentrated phosphoric acid and mix well for use; add m-phenylenedimethyl isocyanate and dibutyltin dilaurate to a three-necked flask equipped with a stirrer, a constant pressure dropping funnel, and a thermometer, and drop the polyester polyol containing concentrated phosphoric acid at room temperature, stir mechanically and heat to 50-80°C for 2-6 hours, and determine the -NCO content by the di-n-butylamine method. When the reaction reaches the metering point, add an excess of HEA and a mixture of inhibitors, and continue to react for 1-3 hours; when the -NCO content is ≤0.5%, cool the material and store it away from light. By using a specific light-curing resin in combination with a water-absorbing resin, a photoinitiator, a pH indicator, a leveling agent, a water-sensitive salt, etc., after light curing, the coating surface remains dry and at the same time, when it encounters a certain humidity, it absorbs water and changes color to achieve an indicative effect.

[0029] The water-absorbing resin is prepared according to the following steps: acrylic acid and bentonite are placed in a beaker, and water is added to mix; sodium hydroxide solution is added dropwise to neutralize the acrylic acid, N-N'methylenebisacrylamide and ammonium persulfate are added, and the mixture is stirred evenly, and the mixture is stirred at room temperature to polymerize for 1 to 3 hours; the product of the previous step is allowed to stand in a water bath at 60 to 80° C. for 1 to 2 hours, and the system becomes viscous until it becomes a gel; the gel product is taken out, placed in a watch glass, dried to constant weight, cut into pieces, ground into powder, and sealed for storage for later use.

[0030] The acrylate reactive monomer is a mixture of one or more selected from lauryl acrylate, isobornyl acrylate, N,N-dimethylacrylamide, 4-hydroxybutyl acrylate, triethylene glycol dimethacrylate, 1,6-hexanediol diacrylate and 2-phenoxyethyl acrylate. The pH indicator is a mixture of at least one or two selected from phenolphthalein and o-cresolphthalein. The leveling agent is a mixture of one or more selected from silicone leveling agents, acrylate leveling agents and modified acrylate leveling agents. The water-sensitive salt is a mixture of one or more selected from sodium carbonate, potassium carbonate, sodium bicarbonate, ferrous sulfate, sodium silicate, sodium metaaluminate and sodium phosphate. The photoinitiator is a mixture of one or more selected from 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxy-cyclohexyl-phenyl ketone, 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester and methyl benzoylformate.

[0031] The preparation method of the above-mentioned moisture-sensitive UV-curing coating comprises the following steps: mixing and stirring the formulated amount of the photocurable resin, the water-absorbing resin and the acrylate active monomer for 0.5h to 2h; then adding the formulated amount of the pH indicator and the leveling agent, stirring for 0.5h to 2h; then adding the formulated amount of the photoinitiator and the water-sensitive salt, vacuuming (preferably -0.1 to 0MPa, using the instrument produced by China Leierda Instrument Co., Ltd., No. YL10207224), stirring at pressure for 2h to 4h; vacuum defoaming and discharging.

[0032] The above-mentioned moisture-sensitive UV-curable coating is applied, and the moisture-sensitive UV-curable coating changes color when it comes into contact with moisture. Optimally, the moisture-sensitive UV-curable coating is applied on the electronic product packaging, and the light reaction is performed for 5 to 30 seconds to form a moisture-sensitive mark; the light band is a mixture of one or several of the 200nm-760nm bands of a mercury lamp or a UV LED lamp; preferably, the light band is a mixture of one or several of the 250nm-500nm bands of a mercury lamp or a UV LED lamp; more preferably, the light band is a mixture of one or several of the 300nm-405nm bands of a mercury lamp or a UV LED lamp.

[0033] In order to enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only embodiments of a part of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained under the premise of equivalent changes and modifications made by ordinary technicians in the field should belong to the scope of protection of the present invention.

[0034] Example 1

[0035] This embodiment provides a moisture-sensitive UV-curable coating, comprising the following components in parts by weight: 30 g of a photocurable resin, 10 g of a water-absorbing resin, 30 g of an acrylate reactive monomer, 4 g of a pH indicator, 1 g of a leveling agent, 20 g of a water-sensitive salt, and 6 g of a photoinitiator;

[0036] The preparation of the above-mentioned photocurable resin includes the following steps: adding polyester polyol 2000 (300g) into a three-necked flask, distilling under reduced pressure at 110°C for 2h, and then cooling to 40°C; adding a trace amount of concentrated phosphoric acid (3ml, concentration of 85%), mixing and setting aside; adding measured m-phenylenedimethyl isocyanate (280g) and catalyst dibutyltin dilaurate (9g) into a three-necked flask equipped with a stirrer, a constant pressure dropping funnel, and a thermometer, slowly dropping the aforementioned polyester polyol 2000 mixed solution at room temperature, mechanically stirring and heating to 80°C for reaction for 3h, determining the -NCO content by the di-n-butylamine method, and when the reaction reaches the metering point, adding a slightly excessive amount of HEA (hydroxyethyl acrylate, 5.2g) and an inhibitor (0.003g of hydroquinone) mixed solution, and reacting at 70°C for 1h; when the -NCO content is less than 0.5%, cooling and discharging the material, and storing it in the dark;

[0037] The preparation of the water-absorbing resin comprises the following steps: 30g of acrylic acid and 3g of bentonite are placed in a beaker, and 50ml of water is added; 15wt% sodium hydroxide solution is added dropwise to neutralize the acrylic acid (about 5ml), and 100ml of water is added after the addition is completed, and the temperature is lowered to room temperature; a cross-linking agent N-N'methylenebisacrylamide (2g) and an initiator ammonium persulfate (0.12g) are added, stirred evenly, and polymerized at room temperature for a certain period of time (2 hours); the mixed solution is transferred to a beaker, and then statically reacted in a 70°C water bath for 2h, the system becomes viscous or even gelatinous, and the gel is taken out to obtain the product. The product is placed in a watch dish at 105°C for drying (more than 1 day, to constant weight), and it is cut into pieces several times during the process. The dried water-absorbing resin is then ground into powder, sealed and stored for later use.

[0038] The acrylate reactive monomer is composed of the following components by weight: 6 g of isobornyl acrylate, 20 g of 4-hydroxybutyl acrylate and 4 g of N,N-dimethylacrylamide; the pH indicator is phenolphthalein, the leveling agent is an organosilicon leveling agent (SN4341 of Shenzhu Chemical Industry), the water-sensitive salt is a mixture of 10 g of water-sensitive salt sodium carbonate and 10 g of water-sensitive salt sodium aluminate (that is, the mass ratio of water-sensitive salt sodium carbonate to water-sensitive salt sodium aluminate is 1:1), and the photoinitiator is composed of the following components by weight: 1 g of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and 5 g of 1-hydroxy-cyclohexyl-phenyl ketone.

[0039] Under normal temperature and pressure, in a yellow light room or in a light-shielded environment, the preparation method and application of the moisture-sensitive UV-curable coating of this embodiment are as follows:

[0040] S1. Add the formulated amount of light-curing resin, water-absorbing resin and acrylate active monomer into a planetary mixer and mix and stir for 0.5 h;

[0041] S2. Add the formulated amount of pH indicator and leveling agent, and stir for 2 hours; put the photoinitiator and water-sensitive salt into the planetary mixer, evacuate to -0.1MPa (measured by the instrument produced by China Leierda Instrument Co., Ltd., No. YL10207224), maintain the pressure and stir for 2 hours; then perform vacuum defoaming and discharge;

[0042] S3, then the liquid moisture-sensitive UV-curable coating is applied on the electronic product packaging (such as the edge of a mobile phone case) by coating / extrusion, and then placed in a light curing machine for light reaction for 5 seconds to initiate glue curing, thereby obtaining a UV-curable coating with moisture-sensitive effect (the UV curing light source can be a UV LED 365nm, with a light intensity of 500mw / cm 2 ).

[0043] Example 2

[0044] This embodiment provides a method for preparing a moisture-sensitive UV-curable coating and an application thereof, which is basically the same as that in Example 1, except that: 40 g of photocurable resin, 15 g of water-absorbing resin, 20 g of acrylate active monomer, 3 g of pH indicator, 0.5 g of leveling agent, 15 g of water-sensitive salt (i.e., the mass ratio of water-sensitive salt sodium carbonate to water-sensitive salt sodium aluminate is 1:1), and 6 g of photoinitiator.

[0045] Example 3

[0046] This embodiment provides a method for preparing a moisture-sensitive UV-curable coating and an application thereof, which is basically the same as that in Embodiment 1, except that: 50 g of photocurable resin, 5 g of water-absorbing resin, 25 g of acrylate active monomer, 1 g of pH indicator, 1 g of leveling agent, 10 g of water-sensitive salt (i.e., the mass ratio of water-sensitive salt sodium carbonate to water-sensitive salt sodium aluminate is 1:1), and 7 g of photoinitiator (containing 2 g of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and 5 g of 1-hydroxy-cyclohexyl-phenyl ketone).

[0047] Example 4

[0048] This embodiment provides a method for preparing a moisture-sensitive UV-curable coating and its application, which is basically the same as that in Embodiment 1, except that the photoinitiator is 6 g of 1-hydroxy-cyclohexyl-phenyl ketone.

[0049] Example 5

[0050] This embodiment provides a method for preparing a moisture-sensitive UV-curable coating and its application, which is basically the same as that in Embodiment 1, except that the water-sensitive salt is 20 g of water-sensitive salt sodium carbonate.

[0051] Comparative Example 1

[0052] This example provides a method for preparing a UV-curable coating and its application, which is basically the same as that in Example 1, except that the photocurable resin is commercially available Sartomer CN2200.

[0053] Comparative Example 2

[0054] This example provides a method for preparing a UV-curable coating and its application, which is basically the same as that in Example 1, except that no water-absorbing resin is added.

[0055] Comparative Example 3

[0056] This example provides a method for preparing a UV-curable coating and its application, which is basically the same as that in Example 1, except that the amount of the photocurable resin is in excess of 60 parts.

[0057] Comparative Example 4

[0058] This example provides a method for preparing a UV-curable coating and its application, which is basically the same as that in Example 1, except that the water-absorbing resin is in excess of 30 parts.

[0059] The moisture-sensitive UV-curable coatings of Examples 1 to 5, Comparative Examples 1 to 4, and existing Plasma color-changing labels were subjected to performance tests such as appearance comparison, viscosity test, color change indication, and static dust emission. The test results are shown in Table 1.

[0060] The specific test method is as follows:

[0061] Appearance: The product is clean and neat, with clear boundaries between the indicating and non-indicating ink parts, which are easy to distinguish;

[0062] Adhesiveness: It can be pasted on the surface of the material to be plasma treated, and there is no falling off after plasma treatment and water washing process;

[0063] Color change indication: After plasma, the indicator ink changes color from gray to green, which meets the standard and is easy to identify;

[0064] Static dust emission: First test one point on a Class 100 clean bench, then place the sample on it and measure another point to compare the dust particle data before and after placement to confirm whether the sample emits dust exceeding the Class 100 standard.

[0065] Table 1 Performance of the liquid optically transparent adhesive in Examples 1-5 and Comparative Examples 1-4

[0066]

[0067] It can be seen from Table 1 that the moisture-sensitive UV-curable coatings prepared in Examples 1-5 of the present invention have good viscosity, good color change indication, and low static dust emission at a wavelength of 270-800nm. Compared with existing products, it has good application prospects and can completely replace manual lamination positions to achieve automation. Among them, in Comparative Example 1, the purchased resin replaces the homemade resin, and its color change indication is not as good as the synthetic resin; the test results of Comparative Example 2 show that the color change indication will be reduced if the water-absorbing resin is not added; it can be seen from the comparison of Comparative Example 3 that the color change indication sensitivity decreases when the resin ratio is increased; the test results of Comparative Example 4 show that the addition of water-absorbing resin has an effect on viscosity and static dust emission.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. At the same time, the above description should be understandable and implementable for those with ordinary knowledge in the relevant technical field. Therefore, other equivalent changes or modifications that do not deviate from the concepts disclosed in the present invention should be included in the scope of protection of the present invention.

Claims

1. A moisture-sensitive UV-curable coating, characterized in that: Its raw materials include the following components in parts by weight: 30~50 parts of light-curing resin; 5-15 parts of water-absorbing resin; 10-30 parts of acrylate reactive monomer; 1~5 parts of pH indicator; 0.3~1 part of leveling agent; 10-20 parts of water-sensitive salt; 2~7 parts of photoinitiator; The preparation of the photocurable resin comprises the following steps: adding polyester polyol into a three-necked flask, performing reduced pressure distillation at 100-140° C. for 2-4 hours, cooling to ≤40° C., adding a trace amount of concentrated phosphoric acid, and mixing for use; adding m-phenylenedimethyl isocyanate and dibutyltin dilaurate into a three-necked flask equipped with a stirrer, a constant pressure dropping funnel, and a thermometer, dripping the polyester polyol containing concentrated phosphoric acid at room temperature, mechanically stirring and heating to 50-80° C. for reaction for 2-6 hours, determining the -NCO content by a di-n-butylamine method, adding an excess amount of HEA and a mixed solution of an inhibitor when the reaction reaches a metering point, and continuing the reaction for 1-3 hours; when the -NCO content is ≤0.5%, cooling, discharging, and storing in the dark.

2. The moisture-sensitive UV-curable coating according to claim 1, characterized in that: Described water-absorbing resin is prepared according to the following steps: Place acrylic acid and bentonite in a beaker, add water to mix; drop sodium hydroxide solution to neutralize acrylic acid, add N-N'methylenebisacrylamide and ammonium persulfate, stir evenly, and stir at room temperature to polymerize for 1-3 hours; The product from the previous step was placed in a water bath at 60-80°C for 1-2 hours to react until the system becomes viscous and gel-like. The gel product was taken out and placed in a watch glass to dry to constant weight. After cutting into pieces and grinding into powder, it was sealed and stored for later use.

3. The moisture-sensitive UV-curable coating according to claim 1 or 2, characterized in that: The acrylic acid ester active monomer is a mixture of one or more selected from lauryl acrylate, isobornyl acrylate, N,N-dimethylacrylamide, 4-hydroxybutyl acrylate, triethylene glycol dimethacrylate, 1,6-hexanediol diacrylate and 2-phenoxyethyl acrylate.

4. The moisture-sensitive UV-curable coating according to claim 1 or 2, characterized in that: The pH indicator is at least one selected from phenolphthalein and o-cresolphthalein or a mixture of two thereof.

5. The moisture-sensitive UV-curable coating according to claim 1 or 2, characterized in that: The leveling agent is a mixture of one or more selected from the group consisting of an organic silicon leveling agent, an acrylate leveling agent and a modified acrylate leveling agent.

6. The moisture-sensitive UV-curable coating according to claim 1 or 2, characterized in that: The water-sensitive salt is a mixture of one or more selected from the group consisting of sodium carbonate, potassium carbonate, sodium bicarbonate, ferrous sulfate, sodium silicate, sodium metaaluminate and sodium phosphate.

7. The moisture-sensitive UV-curable coating according to claim 1 or 2, characterized in that: The photoinitiator is a mixture of one or more selected from 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxy-cyclohexyl-phenyl ketone, ethyl 2,4,6-trimethylbenzoylphenylphosphonate and methyl benzoylformate.

8. The method for preparing the moisture-sensitive UV-curable coating according to any one of claims 1 to 7, characterized in that: The following steps are involved: The light-curable resin, water-absorbing resin and acrylic acid ester active monomer in the formula amount are mixed and stirred for 0.5h to 2h; then the pH indicator and leveling agent in the formula amount are added and stirred for 0.5h to 2h; Then add the formulated amount of photoinitiator and water-sensitive salt, evacuate the chamber, maintain the pressure and stir for 2h~4h; defoam under vacuum and discharge the material.

9. Use of the moisture-sensitive UV-curable coating according to any one of claims 1 to 7, characterized in that: The moisture-sensitive UV-curable coating changes color when exposed to moisture.

10. The use of the moisture-sensitive UV-curable coating according to claim 9, characterized in that: The moisture-sensitive ultraviolet light-curing coating is applied on the electronic product packaging and reacted with light for 5 to 30 seconds to form a moisture-sensitive mark.

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